Exhaust-system components such as exhaust manifolds, exhaust pipes, converter cases, and mufflers used in an automobile exhaust system environment are required to have an excellent thermal fatigue resistance, an excellent high-temperature fatigue resistance, and excellent oxidation resistance (hereinafter these properties may be generally referred to as a “heat resistance”). Currently, Cr-containing steels such as steels containing Nb and Si (for example, JFE 429EX (15 mass % Cr-0.9 mass % Si-0.4 mass % Nb) (hereinafter may be referred to as Nb—Si-containing steel)) are often used in applications that require such a heat resistance. In particular, a Cr-containing steel that contains Nb is known to exhibit an excellent heat resistance. However, since the raw material cost for Nb is high, addition of Nb increases the steel manufacturing cost. From the viewpoint of manufacturing cost, development of a steel that exhibits a high heat resistance with a minimum amount of Nb added is required.
To address this issue, Patent Literature 1 discloses a stainless steel sheet whose heat resistance is enhanced by adding Ti, Cu, and B.
Patent Literature 2 discloses a stainless steel sheet whose workability is enhanced by addition of Cu.
Patent Literature 3 discloses a heat-resistant ferritic stainless steel sheet whose heat resistance is enhanced by addition of Ti.
Patent Literature 4 discloses a heat-resistant ferritic stainless steel sheet whose heat resistance is enhanced by addition of Nb, Cu, Ti, Ni, and Al.